1. Field of the Invention
The present invention relates, in general, to electrical watthour meters and, specifically, to watthour meter mounting enclosures for socket adapters and, more specifically, to jaw blades for watthour meter socket adapters.
2. Description of the Art
Electrical power is supplied to an individual site or service by external electrical power line conductors located above or below ground. In a conventional arrangement, electrical power line conductors are connected to terminals in a watthour meter socket mounted on a building wall. Electrical load conductors are connected to another set of terminals in the meter socket and extend to the electrical distribution network in the building. A watthour meter is connected to both pairs of terminals in the meter socket to measure the electric power drawn through the load conductors.
Due to the current trend toward the use of plug-in watthour meters, A to S type socket adapters have been devised which convert A-base type bottom connected watthour meter sockets to receive plug-in watthour meters. Another type of socket adapter has been devised which allows the installation of other devices between the watthour meter socket and a plug-in watthour meter.
Such socket adapters employ a generally annular base having a shell joined thereto and extending outward from one side of the base. Jaw contacts are mounted in the shell and base. Each jaw contact has a female jaw portion disposed interiorly within the shell and a male blade terminal connected to the female jaw portion and extending outward through the base for plug-in connection to the terminals in the meter socket housing.
In previous watthour meter socket adapters, the jaw contacts were of two different constructions. In one construction, the jaw contacts have a folded over design formed of a base wall fixedly mounted by a fastener to the shell of the socket adapter and two spaced sidewalls extending therefrom. The outer ends of the sidewalls are folded over inwardly between the sidewalls and terminate in parallel end flanges which slidably receive a blade terminal of a watthour meter. A blade terminal is usually fixedly connected to the base wall of the jaw contact for connection to jaw contact in a meter socket.
In the second construction, the jaw contacts are formed of a generally planar terminal having opposed first and second ends. An angularly bent spring clip is riveted at one end to an intermediate portion of the terminal and extends to a contact edge disposed in separable engagement with the first end of the terminal to form a jaw for receiving the blade terminal of a watthour meter. The spring clip forcibly biases the watthour meter terminal into secure electrical engagement with the terminal. The second end of the blade terminal extends exteriorly from the base of the watthour meter socket adapter for releasable engagement in a socket jaw contact. A cotter pin is inserted through an intermediate aperture in the terminal to fixedly mount the terminal and jaw contact in position in the watthour meter socket adapter.
The power rating or current carrying capacity of a jaw contact used in a watthour meter socket adapter is determined, in part, by the amount of conductive metal employed in the construction of the jaw contact. It is also known that heat generated within the watthour meter socket adapter or in the jaw contact itself adversely effects the maximum current the jaw contact can carry, with higher temperatures significantly decreasing the maximum current capacity of a jaw contact.
Watthour meter socket adapters have also been provided with power disconnect devices, such as circuit breakers or ground fault circuit interrupters, both for protecting the electrical service as well as, in certain applications, to limit the amount of power supplied to the site, as shown in U.S. Pat. No. 5,572,396. Such power disconnect devices have also been remotely controlled, such as by signals over conductors from the utility company, to temporarily or permanently disconnect electrical power service to a particular site.
However, such power disconnect devices or switches generate a considerable amount of heat within the interior of the watthour meter socket adapter. This heat lowers the maximum current carrying capability of the jaw contacts within the socket adapter. Thus, it would be desirable to provide a jaw contact structure which is capable of dissipating higher quantities of heat so as to increase the maximum current carrying capability of the jaw contact.
In a typical socket adapter, the socket adapter is formed with a base having a bottom wall and a surrounding peripheral flange. A shell is provided with a bottom wall and an annular sidewall extending from the bottom wall to an end mounting flange which mates with a corresponding mounting flange on a watthour meter. The bottom wall of the shell mates with the peripheral flange on the base and is secured thereto, typically by fasteners extending through the bottom walls of both of the shell and base. Aligned slots are formed in the bottom walls of the shell and base and receive jaw blades which have a blade terminal at one end extending through one aligned slot and a jaw contact at an opposed end for mating engagement with a blade terminal on a watthour meter. The blade terminals of each jaw blade extend exteriorly of the bottom wall of the base for releasable engagement with jaw contacts in a watthour meter socket.
The two spaced bottom walls in the shell and base of such a watthour meter socket adapter construction hold the jaw blades without sideways movement. Such jaw blades are typically fixed in position by cotter pins extending through apertures in the exterior portion of the blade terminal of each jaw blade.
While previously devised watthour meter socket adapters function effectively in releasibly connecting a plug-in watthour meter to the watthour socket jaw contacts, it is believed that further improvements can be made to such watthour meter socket adapters to reduce the manufacturing cost of such socket adapters by simplifying the manufacturing steps in constructing and assembling watthour meter socket adapters. It would also be desirable to provide a watthour meter socket adapter having a one piece construction without a separate shell and base. It would also be desirable to provide an improved watthour meter socket adapter in which the jaw blades are supported from sideways movement. It would also be desirable to provide a watthour meter socket adapter with integral means for non-movably mounting each jaw blade in the socket adapter.